Method of forming cavities in explosive.



U. THOMPSON, JR.

METHOD OF FORMING CAVITIES IN EXPLOSIVES. APPLICATION FILED AUG-27,1917.

Patented Feb. 5, 1918.

2 SHEETSSHEET I.

IAN EN TOR By %M /Z)41/1/ ATTORNEY U. THOMPSON, JR. METHOD OF FORMING CAVITIES IN EXPLOSIVES.

APPLICATION FILED AUG.27.1917.

Patented Feb; 5, 1918.-

2 SHEETSSHEET 2 ATTIOHIVEV plug or core, the core UNITED s'ra'rn ULDRIC THOMPSON, JBh; OF NEW YORK, N. Y.,

ASSIGNOB, BY MESNE ASSIGNMENTS, 'IO

BEBTBOM, ,GBISCO'M 8a CO., INC., A. CORPORATION 01E NEW YORK;

METHOD OF FORMING CAVITIES IN EXPLOSIVES.

Specification of Letters Patent.

Patented Feb. 5, 1918.

Original application filed November 20,1916, Serial No. 132,241. Divided and this application filed August J r., a citizen of the United States, residing at city, county, and State of New York, have invented new and useful Improvements in Methods of Forming Cavities in Explosives, of which the following is a specification.

This invention relates torapidly and safely forming recesses in high explosive material as, for example forming in high explosive shells recesses adapted to receive exploders or detonators.

This application is a division of my application Serial Number 1323M, filed November 20th, 1916 (now Patent Number 1,238,362 patented August 28th, 1917).

In producing high explosive shells it is customary to employ a steel shell having a cylindrical bore of a given diameter throughout almost its entire length and having a cylindrical bore of somewhat greater diameter end or mouth, thus affording an annular shoulder in the plane between the bores of the two diameters against which rests the head through which passes the detonator When the shell is completely assembled. The shell is first filled with high explosive material in molten form, the shell being filled completely, including the portion of the larger diameter at the mouth of the shell, so that the casting of explosive material is free From pipes and blowholes, the explosive material is removed from the portion. of: the shell of larger diameter and an axial hole of relatively small diameter is drilled in the explosive material contained in the portion of the shell of smaller diameter, so that the detonator may be inserted into the shell in intimate contact with the explosive material. Heretofore it has been the practice to follow one of the following methods in producing a shell of the character outlined above. The first method consists in removing the material from the larger portion of the shell, 7

i. 6., from the relatively short portion ad jacentits mouth, and boring an axial recess in the explosive material in the smaller portion of the shell by means of a hand drill or a power drill. Another method consists in casting the high explosive around a casting having a cylindrical for a short distance from its open firing. Secondly,

Serial No. 188,382.

base the size of the larger portion of the shell and having an axial protuberance of the proper size to form the axial recess in the explosive material occupying the portion of the shell of smaller diameter. However, both of these methods are unsatisfactory, the first for the reasonthat it is slow,tedious and unsafe, and the latter for the reason that the cast material contains blowholes and coarse crystals which seriously afiect the density and explosive qualities of the shell 7 and which leave the shell underveight.

Furthermore, any method by which a portion of the explosive material is removed after the shell has been filled with cast material involves certain vital requirements among which may be mentioned the following. In the first place, great accuracy must be employed not only so will be in intimate contact with the remaining explosive material, thereby properly to detonate the mass, but also so that the detonator will not jam when inserted before in removing the explosive material occupying the larger portion of the shell adjacent its mouth, the material must be cut accurately to the plane defined by the shoulder between the two portions of the shell of large and small bore, respectively, for the reasons that if the material is removed to a plane rearwardly of the shoulder the remaining material will not be held in place but will break loose from the wallsot' the shell thereby making the detonation inwhen the detonator and other parts of the head are placed in position thereby causing the explosive to fall into the detonator recess and jam the exploder. And thirdly, in boring a recess of accurately predetermined depth it is necessary to determine the depth of the recesses with respect to some accurately machined external part of the stock which bears a known relation to the point or plane to which it is desired to bore. In the case of shells of the character described for example, the overall length of the shells may vary considerably due to allowed tolthat the detonator of the shoulder is likely to be broken down I sion and so that the rately and rapldly to bOI'G'IGCGSSBS in ex- 'plosive or other material; to remove 'all of the explosive material from the forward larger portionv of a shell of the type referred to without rubbing the borings be-. tween metals which might cause an exploforward end of the remalnlng material lies precisely in the plane defined by the aforesaidinternal shoulder of the shell, and to bore an axial recess in the explosive material occupying the rearward portion of the shell of smaller bore; and to provide for properly positioning the shell or other stock with respect to a boring tool arranged to reciprocate back and forth along a fixed path.

Other'objects of the invention will be apparent from the disclosure of the particular illustrations of my invention hereinafter more fully andat large set forth in connection with the accompanying drawings, in which Figure 1 is a side elevation ofthe indicator type of apparatus whereby "the method may be practised.

Fig. 2 is a top "shown-in Fig. 1;

Fig. 3 is a front elevation of the. apparatus shown in Fig. 1; v

Fig. 4 is an enlarged top view of aportion of the apparatus showing the guide for laterally positioning the stock in alinement with the boring tool;

section showing the paratus as a whole Fig. 5 is an enlarged vertical longitudinal means for both laterally and longitudinally positioning the stock with relation to the boring tool; and

v Fig. 6 is an enlarged vertical longitudinal section of another embodiment of apparatus showing constant stop means for longitudi nally positioning the stock.

As illustrated in Figs; 1, 2 and 3, the apcomprises a boring pmdlelmounted to reciprocate vertically in bearings 2 and arranged to be reciprocated by means of a bell crank 3 pivotallymounted at4 and engaging the lower end of the boring spindle'l by means of a 'pin and slot cbnnection 6. Above the boring i sleeve 13. The boring i a base 9 which in'turn spindle and in alinement therewith, is the mounting head? havin a vertical longitudinal inner bore adapter? to receive the shell head is mountedonis secured to the upthe foot piece 12.

tight. 11 mounted on head? is mounted Within the supporting.

plan view of the apparatus adjusted i pulley 19 on the boring spindle, openings 21 the tubular shell sleeve or guide 13 which as an'outer diameter somewhat smaller than the inner diameter of the mounting head 7 and which is adapted to be laterally boring tool and boring spindle by means of) screws 14 extending through the mounting head. In.order to remove-the material -cut away by the boring tool a hollow casing 16 is provided immediately beneaththe mount- 7 ing head 7 which communicates with a pipe 17 leading to an-exhaust fan or other suit able means for withdrawing the borings f rom the casing. Suitable means for rotatto accurate alinement with the ing the boring spindle comprises awbelt 18 extending between a source of power and the being provided in the base '9 and vertical support 11 to permit the passage of the In order to limit the upward moveas tool and thereby accu-v belt. ment of the boring rately bore the stock to a predetermined depth, a stop 22 may be'adjustably mounted on theboring spindle by means of a set screw 23 and arranged in such manner as to engage the lower side of the lower bearing 2 when the boring spindle has reached its proper'u'ppermost position.

Referring to the more detailed showing of I the mounting head? and shell sleeve 13 and shell rately to center the b ect to the shell 26, and as other parts shown-1n Figs. land 5, it is evident that the shell sleeve may be laterally adjusted by means of the screws 14. accuoring spindle .and boring tool with resp above noted it is not only necessary laterally to adjust the shell with respect to the"boring tool, but it is also essential that the shell be longitudinally positioned with respect to the path of reciprocation of'the boring tool so that the cutting collar 27 on the borin tool will cut to the horizontal plane define by the shoulder 28 between theportion 29 of the shell, which is of larger diameter, and

the portion 31 of smaller diameter which extends from theshoulder 28 the shell.

The preferred means for longitudinallypositioning the shell comprises a 'collar 32 to .the base of v having an annular shoulder 33 adapted to support a sleeve 34 of Babbitt or other suitable bearing material, this entire means and particularly the bearing sleeve '34 con'stitut-. ing a stop to limit the downward movement of the shell. as being threaded on the lower end of the sleeve 13 it may sleeve in any other suitable manner, and indeed, it may be 'lhe inner bore of the bearing 34-is tapere'; In such manner as accurately be. connected to the to fit oyer the While the collar 32 is shown mounted. on supportin A meana other than the sleeve 13, if dosir 7 or they may ward face of the flange 33. The clamp 36 is' provided in an interior recess of the shell sleeve 13 in contact with the outer surface of the shell 26 and by means of the screw spindle 37 and handle 38 is adapted to be forced against the shell under considerable pressure and thereby securely hold the shell in fixed position with respect .to the shell sleeve 13 after ithas been properly positioned by means of the adjusting collar 32.

In order accurately longitudinal position of the shell .26, an 1ndicating lever 39 is arranged to contact with the forward edge of the shell 26 at one end and to play over an indicating scale 42 at the other end. The indicating lever is preferably mounted near the shell end so that the free end of the lever playing over scale 42 will have a considerable range of movement and thereby afiord greater accuracy of indication. A convenient means of so mounting the indicating lever comprises a rod 43 adj ustably mounted in collars 44, bent inwardly at its lower portion and pivotally connected with the indicating lever at 46. The collars 44 may be mounted directly upon the mounting head be mounted by means of a pivotal connection upon the heads of the screws 14 in such manner that the screws and screw heads may be rotated without rotating the collars 44. The latter is the preferred method of mounting the rod 43 for the reason that it affords a very convenient means of automatically positioning the lower end of the indicating lever axially with respect to the shell 26, inasmuch asthis form of mounting meansmaintains the distance between the axis of the shell and the rod 43 constant, this distance being determined by the radius of the shell plus the thickness of the shell sleeve 13 plus the length of the adjusting screws 14.

In the modified form of apparatus. illustrated in Fig. 6 the indicating mechanism shown in Figs. 4 and 5 is replaced by a plate 47 secured to the forward face of the flange 33 by means of stud bolts 48 and thereby bearing. .a constant and fixed relation to the adjusting collar 32. The shell 26 bears against the upper face of the plate 47 around the periphery of the opening which is concentric with the boring tool and which is of slightly greater diameter than the larger bore of the shell, the plate 47 functioning as astop.

The operation of the indicating ,type of apparatus illustrated in Figs. 1 to 5, is as follows: The shell 26 after being entirely filled with cast explosive material is inserted in the shell sleeve 13 from the top until the forward tapered portion of the shell is seat-. ed in the bearing 34. The shell sleeve 13 is first centered with respect. to

reciprocation of the boring tool by means to indicate theproper posed around the cutting to the plane of the shoulder the path of 7' by turning either to raise or to lower the shell as required. The cutting collar 27 is of substantially the same diameter as the'smaller internal bore 31 of the shell and when it has been advanced to the plane defined by shoulder 28 only a very thin ring of explosive material is left adjacent the edge of the shoulder so that the ring of explosive material discollar 27 in the larger portion'29 of the shell is easily Withdrawn from the mouth of the shell and may even fall out due to its own weight when the cutting collar reaches the plane of the shoulder 28. Owing to the fact that the cutting collar 27 is of slightly smaller diameter than the smaller internal bore of the shell it does not make contact with the shoulder 28 and thereby a common cause of premature explosions during the boring process is eliminated and the harp cutting edge of the cutting collar is not impaired. The cutting collar 27 is mounted on the shank of the boring tool 25 and is so disposed longitudinally of the boring tool that when the cutting 'collar reaches the plane of shoulder 28 the boring tool has advanced the proper distance into the portion of the shell of smaller diameter to bore a suitable recess for the detonator.

In initially adjusting the path of reciprocation of the boring tool and in determining the normal position of the indicating lever either one of the following methods is satisfactory. -The first method comprises first making a normal mark on the scale 42 as indicated at 51, adjusting the shell 26 longitudinally until the lever arm stands at the normal position, and then by means of one or more trial borings adjust the stop collar 22 on the boring spindle 1 so that the cutting collar 27 can be advanced only 28. The other method comprises first adjusting the stop collar 22 into approximately the correct position, then longitudinally adjusting the shell to the proper position by means of collar 32, after making one ormore trial borings, and finally making a mark on the indicating scale 42 at the end of the indicating lever which thereafter constitutes the normal indicating point.

Owing to the fact'that the shell is supported by means of the tapered bearing around its forward end instead of means of a stop engaging its forward edge, the space beneath the'mouth of the ishell'is left comparatively open so that the material cut" away by the boring tool can freely fall from the recess and be removed by "the suction late upon my shell /the proper. longitudinal position, after the nated. The d usual support disposed beneath the shell is eliminated, thereby avoiding explosions resulting from blows upon this materialupon the insertion of new shells into the apparatus. Moreover,

a false height relative to the travel of the boring tool.

The operation of the modified apparatus illustrated in Fig. 6-is similar to that of the apparatus shown the precedin figures in -so far as the determination of t e positionof the stop collar 22 on the spindle l and the determination of the position of adjusting collar 32 on owever, owing to the shell being supported at'the lower edge instead of upon a bearing surface engaging its tapered forward portion, it is automatically brought to rest in parts have been properly adjusted, and the necessity of indicating mechanism is elimianger of an explosion resultmg from borings accumulating on the plate 47 and being detonated by dropping a new shell upon them is avoided by makin the opening 49 somewhat larger than the mner bore of the mout .of the shell and by pro- 1 viding suction apparatus for carrying away the borings as they are formed, and the shell is properly positloned longitudinally.-

Although the above described modifications of apparatus, which have been selected for the. urpose of illustration, comprise two simple ibrms, it is evident that the methods 1 employed in connection with these modifications may herein disclosed need not be operated in pre-- cisely the position -shown.in the drawings,

that is, m precisely a vertical position, but

- isof utility when employedin any position 1 tion other than a horizontal position andwherein the opening in the shell is directed somewhat downwardly, that1is, in any posiother than a position in which the base of the shell is lower than the mouth of the shell. In order broadly to recite a position other than the two last meutionedixositions, Ihave employed the expression a ed path having a verticalcomponent, meaning by this a path other thanone disposed horizontally. While in accordance with the-patent stat- I utes, the improved method has been illusit maybe-carried out apparatus bywhich it may be performed, it.

trated by reciting irr'detail steps by which and in connection with out departing no mounds can accumu-- support to give the shell shell sleeve 13 is concerned.

action of gravity,

plosive material contained in a shel the diameter of the lesser 3. The method of forming a cavity in exdirectly explosive contained in th from the larger bore carried out simultaneously, with the boring of smaller diameter, the ,diameter e of the boring in the explosive of the smaller shell bore being'jless than the diameter, of explosive of the larger is to be understood that the details may be 7 varied and that it may be "carried out by other apparatus than that illustrated withi from its spirit; it is not therefore, limited to the precise details recited nor to practice with the apparatus shown in the drawings, the inventionbemg pointed out in the appended claims as required by.

the patent statutes.

What I claim is+ 1. The method of forming a cavity in ex plosive contained in a she 1n supporting the shell with its axis having a vertical component whereby the borings tend to drop away from the shell under the form the desired cavity by relatively'moving a drill and the shell whereby the drill enters into the explosive from the lower end of the shell along a path having a vertical component and conveying the borings of explosive away frointhe vicinity of the shell and drill by suctio X 2. The method of forming a cav' y in exdlrectlycommunicating bores of diflerent diameters,

and having its lower end 1 open, and removing explosive material to,

which consists in boring out the which, consists 'L explosive contained in the bore of larger I d1ameter,'on a diameter not greater than bore.

plosive material contained in a shell having communicating bones of different diameters, which consists in boring out the diameter, on a diameter not greater than the diameter of the lesser bore and removing s1ve.

4., The method of formin plosive contained in a shel 1n relatively whereby the sive and limiting the enetration of the drill by the end of the sheil at its mouth.

. 5. The method'of formang a cavity in explosive containedina shell diflerent diameters, which consists in the remaining explos v bore of larger Q a cavity in ex? which consists movingthe shell and a drill drill is entered into the expIo-' having bores" of or-' diameters the expl sivecontained in the difi'erentbores respectively,

the boring of larger out simultaneously with a portion of the boring of smaller diameter. l

6.- The method of forming a cavity in explosive contained in a shell having bdres of different didmeters,

tively, the boring of larger diameterrbeing a portion of the boring in the;

diameter being carried I which consists in boring out on different diameters the explosive contamed in the different shell bores respec 126 shell bore and the latter boring being not leased tends to drop away fro'm' the shell, greater in diameter than the smaller shell and having its lower end open, and removbore. ing explosive material to form'the desired 7 The method of forming a cavity in ex cavity by relatively moving the shell and plosive cast in a shell having bores of difdrills or cutters of difierent diameters and ierent diameters, which consists in advancin longitudinally fixed relationship, whereing boring cutters or'drills in fixed longituby the said drills or cutters enter into the dinal relationship into the said explosive, the explosive from the lower, open end of the said cutters or drills being of difierent dishell along a path having a vertical comameters to form holes of difierent diameters ponent and the boring of large diameter is in the diiierent bores respectively, the hole carried-out simultaneously with a portion of larger diameter in the larger'shell bore of the boring of smaller diameter.

being not greater than the lesser bore. 10. The method of forming a cavity in 8. The method 'of forming a cavity in exexplosive contained in a shell whichconsists 5 plosive cast in a shell having bores of difin supporting the shell with'its axis having ferent diameters,'which consists in 'support-' a vertical component, whereby explosive re:

ing the shellwith its axis having a vertical leased tends to drop away from the shell, component whereby bor'ngs released tend to and having its lower end open, removing drop away from the shell and having its explosive material to form the desired 55 lower endopen, removing explosive matecavity by relatively moving the shell and rial to form the desired cavity by advancing drills or cutters of different diameters and drills or cutters in longitudinally fixed revin longitudinally fixed relationship, 1wherelationship into the explosive from the lower by the said drills or cutters enter into the end of the shell along a ath having a verexplosive from the lower,- open e d et the v 25 tical component, the sai cutters or drills shell along a path having a v'e ical cornforming holes of diiierentdiameters and the ponent and the boring of larger diameter hole in the larger bore being'of a diameter is carried out simultaneously with a pornot greater than the diameter of the smaller tion of the boring oi smaller diameter and bore, and gaging the penetration of the conveying the ,borings of explosive away drills or cutters into the explosive by referfrom the vicinity of the shell and drill byence tothe forward end of the shell. suction. I I

9. The method of formin a cavity in ex In testimon whereof I have signed this plosive contained in a shel which consists specification t is 25th day of August 1917. in suppo'rtmgthe shell with its axis having 3 a vertical component, whereby explosive 're- ULDRIC THOMPSON, Jn. 

